/* Copyright (c) 2021, LiWangQian<liwangqian@huawei.com> All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of
 *    conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list
 *    of conditions and the following disclaimer in the documentation and/or other materials
 *    provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors may be used
 *    to endorse or promote products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#pragma once

#include <libmsg/messages/message_wrapper.hpp>
#include <condition_variable>
#include <mutex>
#include <memory>
#include <queue>


namespace libmsg {

/**
 * @brief FIFO的消息队列
 */
struct message_queue {
    using message_ptr = std::shared_ptr<messages::message_base>;

    void push(message_ptr msg)
    {
        std::lock_guard<std::mutex> lk(m);
        q.push(msg);
        c.notify_all();
    }

    message_ptr wait_and_pop()
    {
        std::unique_lock<std::mutex> lk(m);
        c.wait(lk, [&]{ return !q.empty(); });
        auto msg = q.front();
        q.pop();
        return msg;
    }

private:
    std::mutex m;
    std::condition_variable c;
    std::queue<message_ptr> q;
};

} // namespace libmsg
